A high-current amplifier, like other amplifiers, takes an audio signal and amplifies its size and power. What distinguishes a high-current amplifier is its ability to generate high amperage in addition to voltage. This unique capability enables high-current amplifiers to drive challenging speakers and multiple speakers simultaneously.
The components of Amplified Power: Voltage, Amperage, and Impedance
To understand the value of a high-current amplifier, it’s essential to grasp the components of power. The power delivered by an amplifier, measured in watts, results from a combination of voltage and amperage. Voltage measures the “pressure” of the power flow, while amperage gauges the actual flow of electrons over time. Wattage is calculated by multiplying voltage and amperage. For instance, a low-current amplifier might produce 100 watts by sending 4 amps at 25 volts, whereas a high-current amplifier could achieve the same wattage with 16 amps at 6.25 volts.
Impedance Considerations for High-Current Amplifiers
Impedance plays a crucial role in determining the suitability of a high-current amplifier for a specific situation. Measured in ohms, impedance reflects how much a speaker resists a sent signal. Speakers with lower impedance require a higher current power supply, while those with higher impedance demand less current and more voltage. High-current amplifiers are particularly beneficial for sound systems with low-impedance speakers.
Low Impedance Situations and High-Current Amplifier Benefits
Low impedance often arises in two scenarios. Firstly, high-end speakers, such as large electrostatic “ribbon” speakers, are designed with intentionally low impedance. Secondly, low impedance occurs when multiple speakers are connected to one amplifier channel. For example, connecting two 8-ohm impedance speakers in series results in a 4-ohm impedance presented to the amplifier. This multiple-speaker configuration is common in public address (PA) systems.
Comparing Low-Current and High-Current Amplifiers: Size, Cost, and Performance
In general, low-current amplifiers are smaller, lighter, and more cost-effective to manufacture. High-current amplifiers, in contrast, tend to be larger, heavier, and more expensive. However, the added cost and size bring enhanced performance into low-impedance loads. High-current amplifiers can leverage their extra current capacity to deliver more power into medium and high-impedance loads, improving the reproduction of volume peaks in music and other content.